#region Copyright & License

//
// Copyright 2001-2005 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

#endregion

// .NET Compact Framework 1.0 has no support for ASP.NET
// SSCLI 1.0 has no support for ASP.NET
#if !NETCF && !SSCLI

using System.Web;
using log4net.Core;

namespace log4net.Appender {
  /// <summary>
  /// <para>
  /// Appends log events to the ASP.NET <see cref="TraceContext"/> system.
  /// </para>
  /// </summary>
  /// <remarks>
  /// <para>
  /// Diagnostic information and tracing messages that you specify are appended to the output 
  /// of the page that is sent to the requesting browser. Optionally, you can view this information
  /// from a separate trace viewer (Trace.axd) that displays trace information for every page in a 
  /// given application.
  /// </para>
  /// <para>
  /// Trace statements are processed and displayed only when tracing is enabled. You can control 
  /// whether tracing is displayed to a page, to the trace viewer, or both.
  /// </para>
  /// <para>
  /// The logging event is passed to the <see cref="TraceContext.Write(string)"/> or 
  /// <see cref="TraceContext.Warn(string)"/> method depending on the level of the logging event.
  /// </para>
  /// </remarks>
  /// <author>Nicko Cadell</author>
  /// <author>Gert Driesen</author>
  public class AspNetTraceAppender : AppenderSkeleton {
    #region Public Instances Constructors

    #endregion // Public Instances Constructors

    #region Override implementation of AppenderSkeleton

    /// <summary>
    /// This appender requires a <see cref="Layout"/> to be set.
    /// </summary>
    /// <value><c>true</c></value>
    /// <remarks>
    /// <para>
    /// This appender requires a <see cref="Layout"/> to be set.
    /// </para>
    /// </remarks>
    protected override bool RequiresLayout {
      get { return true; }
    }

    /// <summary>
    /// Write the logging event to the ASP.NET trace
    /// </summary>
    /// <param name="loggingEvent">the event to log</param>
    /// <remarks>
    /// <para>
    /// Write the logging event to the ASP.NET trace
    /// <c>HttpContext.Current.Trace</c> 
    /// (<see cref="TraceContext"/>).
    /// </para>
    /// </remarks>
    protected override void Append(LoggingEvent loggingEvent) {
      // check if log4net is running in the context of an ASP.NET application
      if (HttpContext.Current != null) // check if tracing is enabled for the current context
        if (HttpContext.Current.Trace.IsEnabled)
          if (loggingEvent.Level >= Level.Warn)
            HttpContext.Current.Trace.Warn(loggingEvent.LoggerName, RenderLoggingEvent(loggingEvent));
          else
            HttpContext.Current.Trace.Write(loggingEvent.LoggerName, RenderLoggingEvent(loggingEvent));
    }

    #endregion // Override implementation of AppenderSkeleton
  }
}

#endif // !NETCF && !SSCLI